Apparatus for electrical separation of suspended particles from gases.



I W. A. SCHMIDT (IL 6. C. ROBERTS. APPARATUS FOR ELECTRICAL SEPARATION OE SUSPENDED PARTICLES FROM GASES.

APPLICATION FILED SEPT. 9. I913.

1,252,188 Patented Jan. 1,1918

"the electrodes.

WALTER A. SCHMIDT AND GEORGE C. ROBERTS, OF LOS ANGELES, CALIFORNIA, ASSIGN- ORS TO INTERNATIONAL PRECIPITATION COMPANY, OF LOS ANGELES, CALIFORNIA,

A CORPORATION OF CALIFORNIA.

APPARATUS ELECTRICAL SEPARATION OF SUSPENDED PARTICLES FROM GASES.

Application filed September 9, 1913.

To all whom it may concern:

Be it known that we, WALTER A. SCHMIDT and GEORGE C. ROBERTS, citizens of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented a new and useful Apparatus for Electrical Separation of Suspended Particles from Gases, of which the following is a specification.

This invention relates to means for separation of suspended particles from gases by electrical action. In such action the particles are electrically charged and then precipitated by the action of electrostatic force on the charges of the particles. In order to charge the particles it is necessary to dis-' charge electricity into the gas containing the particles, and in practice the gas is passed between opposing electrodes, between which is produced an electric field of suflicient intensity to cause ionization of the gas and consequent discharge of electricity from In general, there will be ionization and discharge of electricity from both of the opposing electrodes, so that the particles adJacent to the respective electrodes receive charges of opposite sign and migrate in opposite directions. Charged particles, migrating from either electrode toward the other electrode, are liable to be discharged by the action of ionization from such other electrode, with resultant failure in precipitating force thereon, or to receive reverse charges, resulting in backward migration, the conflicting ionizations therefore tending to permit the particles. to pass through the electrostatic field Without being precipitated. T

One object of the present invention is to prevent, as far as possible, the loss in. efliciency and capacity resulting from such conflicting actions. To attain this result it is necessary to substantially eliminate the discharging action at one of the electrodes while maintaining maximum .discharging action at the other electrode, so that ionization proceeds only from one electrode and migration proceeds only toward the other electrode and is uninterrupted until the particles reach and are collected upon such other electrode.

lVe have found that this result can be best secured by forming the collecting electrodes as cylinders, with the ionizing electrodes as Specification of Letters Patent.

Patented Jan.i,il918.

Serial No. 788,817.

straight filaments extending axially in such cylinders, such a construction giving uniform distribution of the field over a greatly extended surface on the collecting electrode, so as to minimize the discharge therefrom, and in order to provide a large capacity without unduly lengthening the field we subdivide the current of gas into numerous streams, passed in parallel through such cylindrical collecting electrodes.

Another object of the invention is to provide for protection of the electrodes from the effects of excessive or disruptive discharge where they pass the edges of the collecting electrodes, these being the places where the field intensity and discharging action are strongest.

The accompanying drawings illustrate an apparatus embodying our invention, and referring thereto:

Figure 1 is a vertical section of the apparatus on the irregular section line 11, of

. Fig. 2.

Fig. 2 is a plan thereof.

Fig. 3 is a vertical section showing one end of a treating flue and the electrodeportion adjacent thereto, with its supporting and protecting means.

Figs. 4 and 5 are sectional views, showing other forms of the protecting means.

1 designates the flue or conduit which delivers to the apparatus the gas to be treated. The precipitating apparatus comprises a plurality of pipes, tubes, or flues 2, connected, for example, at their lower ends, to a header 3, in communication with the supply fiue 1, said pipes being open at their up per ends, so as to discharge into the outer air or into any suitable means .for carrying off the clarified gas. The lines or pipes 2 are cylindrical or substantially so, and constitute the collecting electrodes for the ap paratus, being, for example, of conducting material and grounded by connection to the header 3.

The ionizing electrodes 4 are formed as straight linear conductors, preferably filaments or fine Wires (say one twentieth inch, or less, in diameter) extending axially in the cylindrical flues 2 and supported by any suitable means, for example, by a suspension wire 5, mounted on insulating supports 6, and having the electrode filaments 4 hung therefrom. A retaining bar 7 is preferably provided near the other end of the electrode filaments, to retain them in proper position, and suitable means, such as weights 8, are preferably provided for tensioning the filaments 4: to hold the same extended in axial relation to the cylindrical flues 2.

In order to protect the filaments or wires 4 from the. tendency to excessive discharge at the places where they pass the edges of the openings at the ends of the flues 2, we

- provide means for reducing the field intensity at these points. For this purpose we may use tubes or sleeves 9, of either conducting or non-conducting material, surrounding the upper portions of the ionizing electrodes 4 and hung, for example, on the suspension wire 5, as shown in Figs. 1 Similar sleeves or tubes 10 may surround the lower portions of the electrodes 4, and are supported, for example, on the retaining bar 7.

In case sleeves 9 and 10 are of insulating material, they prevent breaklown of the dielectric by increasing the resistance to disruptive discharge. In case they are of conducting material, they increase the effective diameter and reduce the sharpness of curvature of theelectrodes at these places, with the result that the surface field intensity, and consequent electric discharge are also reduced, so as to obviate the liability to disruptive discharge. The same effect may be secured by' enlarging the filament or electrode itself at these parts, as shown at 12 in Fig. 1. Or, as indicated at 13 in Fig. 5,

these parts of the ionizing electrode may be surrounded or covered by a solid insulating sleeve or coating 13, which prevents break-clown of the dielectric. The ends of i the flues 2 may also be flared, as shown at 2 to assist in the reduction of field intensity at these portions of the apparatus.

The ionizing electrodes 4 may be connected to any suitable charging circuit, such as indicated at 14, provided with means indicated at 15 for generating or supplying unidirectional current of high voltage, the said supply means being grounded as shown at 1 6 and the header being grounded, as at 17. i

The operation of the apparatus is as follows The ionizing electrodes being axially arranged in the cylindrical collecting electrodes, the electrical action is uniformly distributed over the surfaces of the collecting electrodes, and by reason of the greatly extended area of such surfaces as compared with the area of the surfaces of the ionizing electrodes, and of the concave curvature of the collecting electrodes, as compared with the sharp convexity of the ionizing electrodes,'the surface field intensity at the collecting electrodes is negligible compared with that at the ionizing electrodes 4, so that the ionization proceeds only from the electrodes l, and the migration of the dust or other solid or liquid particles under the action of the electrostatic field between the electrodes proceeds unchecked until the particles reach the collecting electrodes.

\Vhat we claim is:

1. An apparatus for electrical separation of suspended particles from gases comprising a multiplicity of collecting electrodes in the form of vertical pipes, a support extending over said pipes and spaced and insulated therefrom, discharge electrodes in the form .of plain or smooth wires supported from said insulated support and extending axially into said pipes, and means'for passing gases through said pipes.

2. Apparatus for electrical separation of suspended particles from gases, comprising a chamber provided with a gas flue connection, a multiplicity of collecting electrodes in the form of vertically extending tubes opening at one of their ends into said chamber, and open at their other ends, asupport extending over said tubes and insulated therefrom, and discharge electrodes formed as flexible members hung from said support and extending axially in the respective tubes.

3. An apparatus for electrical separation of suspended particles from gases comprising a chamber provided with a gas inlet, a multiplicity of collecting electrodes in the form of vertical pipes opening at their lower ends into said chamber and open at their upper ends, a supportextending over said pipesv and insulated therefrom, and discharge electrodes formed as flexible membershung from said support and extending axially into the respective pipes, said flexible members being weighted to hold them taut.

4. An apparatus for electricalprecipitation of suspended particles from gases comprising a vertically extending pipe, and a straight filamentary ionizing electrode extending axially intothe pipe.

5. An apparatus for electrical separation of suspended particles from gases, comprising a header provided with a gas inlet. a multiplicity of collecting electrodes in the forin of vertical pipes connected at their flexible members liw 'i a C lower ends to said headerandopen at their upper ends, a support extending over said pipes and spaced and insulated therefrom, and dischar'g'e electrodes formed as flexible members hung from 'said support and ,extending axially in being -.weighted to hold them taut. e

6. An apparatus for electrical separation of suspended 1 particles from, gases, comprising a header provided with a gas inlet,.a...

multiplicity of vertically extending pipes connected to said header, a supporting means extending over said pipes, and spaced and insulated therefrom, discharge electrodes formed as flexible members hung from said supporting means and extending axially in the respective pipes, and means extending below said pipes and insulated therefrom and engaging said flexible members to hold the same from lateral movement. v

7. In an apparatus for electrical separation of suspended particles from gases, a

vertically extending, collecting electrode, an insulated support above and spaced from said collecting electrode, an ionizing electrode formed as a conducting filament, hung from said support and extending vertically along the axis of the cylindrical collecting electrode, and extending past the upper and lower edges of the collecting electrode, and a weight on the lower end of said filament to hold the same in straight vertical position. I

8. In an apparatus for electrical separation of suspended particles from gases, a

substantially cylindrical vertically extending collecting electrode, a-support, an ionizing electrode formed as a filament suspended from said support, and extending vertically along the axis of said cylindrical electrode, a weight on the lower end of said filament, and retaining means engaging said header, supportin I filament to prevent lateral movement thereof.

9. An apparatus for electrical separation of suspended particles from gases comprising a header '.for receiving the gases, a plurality of substantially cylindrlcal collecting electrodes extending vertically from said means insulated from I said collecting e ectrodes and extending above the same and a plurality of straight filamentary ionizing electrodes, suspended from said supporting means and extending vertically along the axes of the respective collecting electrodes, and past the upper and lower ed es of said col ecting electrodes,

a and weig ts hung on the lower ends of said ionizing electrodes.

10. Anapparatus for electricalseparation of suspended particles from gases, comprising a header for conducting the gases, a plurality of substantially cylindrical collecting electrodes extending vertically from said header, supporting means insulated from the respective pipes, said -.said..c ollecting electrodes. .and extending above the same, a plurality of straight filamentary. ionizing electrodes, suspended -.weights hungon the lower ends. of said ionizing electrodes, and a retaining means having openings through which. the: ionizing-=electrodes pass, whereby said ionizing electrodes are held from lateral movement.

11. An apparatus for electrical separation of suspended particles from gases comprising aheader provided with means for supplying gas thereto, a plurality of substantially cylindrical collecting electrodes extending vertically from said header and open at their upper ends, a support extending above said collecting electrodes and insulated therefrom, and filamentary ionizing electrodes hung from said support and extending axially in said collecting electrodes, and extending into said-header, and weights hung on the lower ends of said ionizing electrodes to hold them under tension. I 12. In an apparatus for electrical separation of suspended particles from gases, a collecting electrode having an extended surface, an ionizing electrode formed as a filament parallel to the collecting electrodeand extending at one end beyond the edge of said collecting electrode, the space between the two electrodes adjacent to such edge, being open, forfree passage of gas, and said ionizing electrode having an enlargement, adjacent to such edge, to reduce the surface field intensity at the adjacent portion of the ionizing electrode. a F

13. In an apparatus for electrical separation of suspended particles from gases, a substantially cylindrical collecting electrode, an ionizin electrode extending axially through said cylindrical electrode and extending beyond the edges thereof, and having enlargements adjacent to such edges, to reduce the surface field intensity at such points,'the space between said enlargements and the collecting electrode being open for free passage of the gases.

14. In an apparatus for electrical separation of suspended particles from gases, a substantially cylindrical vertically extending, collecting electrode, open at its upper end, meal ls for supplying gas to the lower end of said electrode, a sup ort insulated from said collecting electro e and spaced therefrom to permit passa e of gas from the end of said electr e, and an ionizin electrode suspended from said support an extending axially through the collecting electrode and provided with means for reducing the surface field intensity where it passes the edge of the collecting electrode.

15. An apparatus for electrical separation 130 ofsuspended particles from gases, co1nprissupport and extending axially in the re ing a horizontally extending header, a mulspective pipes." l tiplicity of vertically extending pipes con- ALTER A SCHMIDT nected at their lower ends to said header and a i open at their upper ends, an insulated sup- GEORGE ROLLRTD port extending over said pipes and spaced Witnesses:

therefrom, and a multiplicity of discharge WM, N. DREW, electrodes supported from said insulated MARGARET A. GUISE. 

